Ocular implants for delivery into an anterior chamber of the eye

ABSTRACT

An ocular implant adapted to be disposed within Schlemm&#39;s canal of a human eye with a body extending along a curved longitudinal central axis in a curvature plane, a first strut on one side of the implant and a second strut on an opposite side of the implant, the circumferential extent of the first strut with respect to the plane of curvature being greater than the circumferential extent of the second strut with respect to the plane of curvature. The invention also includes methods of using the implant.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit under 35 U.S.C. §119 of U.S. PatentAppl. No. 61/635,104, filed Apr. 18, 2012, the disclosure of which isincorporated by reference.

INCORPORATION BY REFERENCE

All publications and patent applications mentioned in this specificationare herein incorporated by reference to the same extent as if eachindividual publication or patent application was specifically andindividually indicated to be incorporated by reference.

FIELD

The present invention relates generally to devices that are implantedwithin the eye. More particularly, the present invention relates tosystems, devices and methods for delivering ocular implants into theeye.

BACKGROUND

According to a draft report by The National Eye Institute (NEI) at TheUnited States National Institutes of Health (NIH), glaucoma is now theleading cause of irreversible blindness worldwide and the second leadingcause of blindness, behind cataract, in the world. Thus, the NEI draftreport concludes, “it is critical that significant emphasis andresources continue to be devoted to determining the pathophysiology andmanagement of this disease.” Glaucoma researchers have found a strongcorrelation between high intraocular pressure and glaucoma. For thisreason, eye care professionals routinely screen patients for glaucoma bymeasuring intraocular pressure using a device known as a tonometer. Manymodern tonometers make this measurement by blowing a sudden puff of airagainst the outer surface of the eye.

The eye can be conceptualized as a ball filled with fluid. There are twotypes of fluid inside the eye. The cavity behind the lens is filled witha viscous fluid known as vitreous humor. The cavities in front of thelens are filled with a fluid know as aqueous humor. Whenever a personviews an object, he or she is viewing that object through both thevitreous humor and the aqueous humor.

Whenever a person views an object, he or she is also viewing that objectthrough the cornea and the lens of the eye. In order to be transparent,the cornea and the lens can include no blood vessels. Accordingly, noblood flows through the cornea and the lens to provide nutrition tothese tissues and to remove wastes from these tissues. Instead, thesefunctions are performed by the aqueous humor. A continuous flow ofaqueous humor through the eye provides nutrition to portions of the eye(e.g., the cornea and the lens) that have no blood vessels. This flow ofaqueous humor also removes waste from these tissues.

Aqueous humor is produced by an organ known as the ciliary body. Theciliary body includes epithelial cells that continuously secrete aqueoushumor. In a healthy eye, a stream of aqueous humor flows out of theanterior chamber of the eye through the trabecular meshwork and intoSchlemm's canal as new aqueous humor is secreted by the epithelial cellsof the ciliary body. This excess aqueous humor enters the venous bloodstream from Schlemm's canal and is carried along with the venous bloodleaving the eye.

When the natural drainage mechanisms of the eye stop functioningproperly, the pressure inside the eye begins to rise. Researchers havetheorized prolonged exposure to high intraocular pressure causes damageto the optic nerve that transmits sensory information from the eye tothe brain. This damage to the optic nerve results in loss of peripheralvision. As glaucoma progresses, more and more of the visual field islost until the patient is completely blind.

In addition to drug treatments, a variety of surgical treatments forglaucoma have been performed. For example, shunts were implanted todirect aqueous humor from the anterior chamber to the extraocular vein(Lee and Scheppens, “Aqueous-venous shunt and intraocular pressure,”Investigative Ophthalmology (February 1966)). Other early glaucomatreatment implants led from the anterior chamber to a sub-conjunctivalbleb (e.g., U.S. Pat. Nos. 4,968,296 and 5,180,362). Still others wereshunts leading from the anterior chamber to a point just insideSchlemm's canal (Spiegel et al., “Schlemm's canal implant: a new methodto lower intraocular pressure in patients with POAG?” Ophthalmic Surgeryand Lasers (June 1999); U.S. Pat. Nos. 6,450,984; 6,450,984). Morerecent glaucoma treatment implants are designed to be advanced into andplaced in Schlemm's canal. (See, e.g., U.S. Pat. No. 7,740,604; US2011/0009958.)

SUMMARY OF THE DISCLOSURE

The present invention relates to methods and devices for treatingglaucoma. In particular, the invention relates to an implant designed toextend from the anterior chamber of a human eye into Schlemm's canal andto support the tissue of Schlemm's canal to support flow of aqueoushumor from the anterior chamber into Schlemm's canal to the outflowchannels communicating with Schlemm's canal.

In one aspect, the invention provides an ocular implant adapted to bedisposed within Schlemm's canal of a human eye and configured to supportSchlemm's canal in an open state. The ocular implant has a bodyextending along a curved longitudinal central axis in a curvature plane,the body having a central channel bordered by an opening, first andsecond frames and a spine interposed between the first and secondframes, the spine having a circumferential extent, the body havingdimensions adapted to be fit within Schlemm's canal; each framecomprising a first strut on one side of the implant and a second struton an opposite side of the implant, the first strut extendingcircumferentially beyond the circumferential extent of the spine on theone side of the implant and the second strut extending circumferentiallybeyond the circumferential extent of the spine on the other side of theimplant, the circumferential extent of the first strut with respect tothe plane of curvature being greater than the circumferential extent ofthe second strut with respect to the plane of curvature. In someembodiments, the body has a curved resting shape.

The implant may be adapted to bend preferentially in a preferentialbending direction. In some embodiments, the preferential bendingdirection is in the curvature plane, and in some embodiments thepreferential bending direction is not in the curvature plane.

In some embodiments, the circumferential extent of the first strutbeyond the circumferential extent of the spine on the one side of theimplant is greater than the circumferential extent of the second strutbeyond the circumferential extent of the spine on the other side of theimplant.

In embodiments in which the implant also has a third frame and a secondspine interposed between the second and third frames, the second spinehaving a circumferential extent, the third frame having a first strut onone side of the implant and a second strut on an opposite side of theimplant, the first strut and second strut of the third frame each havinga circumferential extent greater than the circumferential extent of thesecond spine, the circumferential extent of the first strut with respectto the plane of curvature may be greater than the circumferential extentof the second strut with respect to the plane of curvature. The first,second and third frames may be substantially identical, and the firstand second spines may be substantially identical. In some embodiments,the first spine is adapted to bend preferentially in a first bendingdirection, and the second spine is adapted to bend preferentially in asecond bending direction different from the first bending direction.

In some embodiments, the plane of curvature intersects the spine. Thespine may extend circumferentially in substantially equal amounts fromthe plane of curvature.

In some embodiments, the opening is an elongated opening extendinglongitudinally along the frames and the spine. The implant may also havea second opening bordered by the first and second struts of the firstframe and a third opening bordered by the first and second struts of thesecond frame.

Another aspect of the invention provides a method of treating glaucomain a human eye. The method may include the following steps: inserting acannula through a cornea of the eye into an anterior chamber of the eye;placing a distal opening of the cannula in communication with Schlemm'scanal of the eye; moving an ocular implant out of the cannula throughthe opening and into Schlemm's canal, the ocular implant having acentral channel and first and second landing surfaces, the first andsecond landing surfaces being disposed on opposite sides of the centralchannel; and engaging a scleral wall of Schlemm's canal with the firstand second landing surfaces such that reaction forces on the first andsecond landing surfaces from engagement with the scleral wall aresubstantially equal.

In some embodiments, the engaging step includes the step of engaging thescleral wall of Schlemm's canal with the first and second landingsurfaces without substantially twisting the ocular implant.

In some embodiments, the implant has a resting shape forming a curve,and the method includes the step of orienting the implant curve with acurve of Schlemm's canal.

In some embodiments, the cannula is curved at a distal end, and themethod includes the step of orienting the cannula for tangentialdelivery of the implant from the cannula into Schlemm's canal.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a stylized representation of an exemplary medical procedure inaccordance with this detailed description.

FIG. 2 is an enlarged perspective view further illustrating deliverysystem 70 and eye 20 shown in the previous figure.

FIG. 3A is a stylized perspective view illustrating the anatomy of aneye. FIG. 3B is a stylized perspective view depicting the surface thatdefines the anterior chamber of the eye shown in FIG. 3A.

FIG. 4 is a stylized perspective view showing Schlemm's canal and aniris of the eye shown in the previous figure.

FIG. 5A is a photographic image showing a histology slide HS. Histologyslide HS of FIG. 5A was created by sectioning and staining tissue from acadaveric eye. An ocular implant was implanted in Schlemm's canal of thecadaveric eye prior to sectioning. FIG. 5B is a perspective view of theocular implant used to generate the slide image shown in FIG. 5A.

FIG. 6A is a stylized line drawing illustrating histology slide HS shownin the previous figure. FIG. 6B is a simplified cross-sectional viewillustrating the eye from which the histology sample was taken. FIG. 6Aand FIG. 6B are presented on a single page to illustrate the location ofthe histology sample relative to other portions of the eye.

FIG. 7A is a stylized line drawing showing an ocular implant residing ina section of an eye including Schlemm's canal. FIG. 7B is a section viewshowing the ocular implant prior to insertion into Schlemm's canal ofthe eye. FIG. 7C is a perspective view showing the ocular implant beinginserted into Schlemm's canal.

FIG. 8A is a stylized line drawing showing an ocular implant accordingto the detailed description residing in a section of an eye includingSchlemm's canal. FIG. 8B is a section view showing the ocular implant ofFigure A prior to insertion into Schlemm's canal of the eye. FIG. 8C isa perspective view showing the ocular implant of FIGS. 8A and 8B beinginserted into Schlemm's canal.

FIG. 9 is a perspective view showing the ocular implant of FIG. 7.

FIG. 10 is an additional perspective view showing the ocular implant ofFIG. 8.

FIG. 11A is a stylized perspective view showing a conical surface thatis sized and positioned so as to intersect a hemispherical surface intwo places. FIG. 11B is a stylized perspective view showing an ocularimplant disposed inside a chamber defined by a hemispherical surface.

FIG. 12A, FIG. 12B and FIG. 12C are plan views of the ocular implant ofFIG. 8 created using multiview projection.

FIG. 13A is a plan view showing the ocular implant of FIG. 8. FIG. 13Bis an enlarged section view taken along section line B-B shown in FIG.13A. FIG. 13C is an additional enlarged section view taken along sectionline C-C shown in FIG. 13A.

FIG. 14A is a perspective view showing the ocular implant of FIG. 8. Afirst plane and a second plane are shown intersecting the ocular implantin FIG. 14A. FIG. 14B is a plan view further illustrating the secondplane shown in FIG. 14A.

FIG. 15A, FIG. 15B and FIG. 15C are multi-plan views of a yet anotherocular implant in accordance with the detailed description.

FIG. 16A is a plan view showing the ocular implant of FIG. 15. FIG. 16Bis an enlarged section view taken along section line B-B shown in FIG.16A. FIG. 16C is an additional enlarged section view taken along sectionline C-C shown in FIG. 16A.

FIG. 17A is a perspective view showing the ocular implant of FIG. 15. Afirst, second and third planes are shown intersecting the ocular implantin FIG. 17A. FIG. 17B is a plan view further illustrating the secondplane shown in FIG. 17A. FIG. 17C is a plan view further illustratingthe third plane shown in FIG. 17A.

FIG. 18A is an additional perspective view of the ocular implant shownin the previous figure. The ocular implant 300 of FIG. 18A includes adistal-most spine and a distal-most frame. In the exemplary embodimentof FIG. 18A, the distal-most frame comprises a first strut and a secondstrut. FIG. 18B is a stylized isometric view showing the profiles of thedistal-most spine, the first strut and the second strut shown in FIG.18A.

FIG. 19A and FIG. 19B are perspective views showing distal portions ofthe ocular implant of FIG. 8 and the ocular implant of FIG. 15,respectively.

FIG. 20 is a perspective view showing yet another exemplary ocularimplant in accordance with the detailed description.

FIG. 21 is a stylized perspective view showing Schlemm's canalencircling an iris. For purposes of illustration, a window is cutthrough a first major side of Schlemm's canal in

FIG. 21. Through the window, an ocular implant can be seen residing in alumen defined by Schlemm's canal.

FIG. 22 is an enlarged cross-sectional view further illustratingSchlemm's canal SC shown in FIG. 21.

DETAILED DESCRIPTION

The following detailed description should be read with reference to thedrawings in which similar elements in different drawings are numberedthe same. The drawings, which are not necessarily to scale, depictillustrative embodiments and are not intended to limit the scope of theinvention.

FIG. 1 is a stylized representation of an exemplary medical procedure inaccordance with this detailed description. In the exemplary procedure ofFIG. 1, a physician is treating an eye 20 of a patient P. In theexemplary procedure of FIG. 1, the physician is holding a hand piece ofa delivery system 70 in his or her right hand RH. The physician's lefthand LH is holding the handle H of a gonio lens 23 in the exemplaryprocedure of FIG. 1. It will be appreciated that some physicians mayprefer holding the delivery system hand piece in the right hand and thegonio lens handle in the left hand.

During the exemplary procedure illustrated in FIG. 1, the physician mayview the interior of the anterior chamber using gonio lens 23 and amicroscope 25. Detail A of FIG. 1 is a stylized simulation of the imageviewed by the physician. A distal portion of a cannula 72 is visible inDetail A. A shadow-like line indicates the location of Schlemm's canalSC which is lying under various tissue (e.g., the trabecular meshwork)that surround the anterior chamber. A distal opening of cannula 72 ispositioned near Schlemm's canal SC of eye 20.

Methods in accordance with this detailed description may include thestep of advancing the distal end of cannula 72 through the cornea of eye20 so that a distal portion of cannula 72 is disposed in the anteriorchamber of the eye. Cannula 72 may then be used to access Schlemm'scanal of the eye, for example, by piercing the wall of Schlemm's canalwith the distal end of cannula 72. A distal opening of cannula 72 may beplaced in fluid communication with a lumen defined by Schlemm's canal.The ocular implant may be advanced out of the cannula and into Schlemm'scanal. Insertion of the ocular implant into Schlemm's canal mayfacilitate the flow of aqueous humor out of the anterior chamber of theeye.

FIG. 2 is an enlarged perspective view further illustrating deliverysystem 70 and eye 20 shown in the previous figure. In FIG. 2, cannula 72of delivery system 70 is shown extending through a dome-shaped wall 90of eye 20. The dome shaped wall includes the cornea 36 of eye 20 andscleral tissue that meets the cornea at a limbus of the eye. A distalportion of cannula 72 is disposed inside the anterior chamber AC definedby the dome-shaped wall 90. In the embodiment of FIG. 2, cannula 72 isconfigured so that a distal opening of cannula 72 can be placed in fluidcommunication with Schlemm's canal. In the embodiment of FIG. 2, thedistal end of cannula 72 is curved so that the distal opening of thecannula can be inserted at least partially into Schlemm's canal along atangential approach.

In the embodiment of FIG. 2, an ocular implant is disposed in apassageway defined by cannula 72. Delivery system 70 includes amechanism that is capable of advancing and retracting the ocular implantalong the length of cannula 72. The ocular implant may be placed inSchlemm's canal of eye 20 by advancing the ocular implant through thedistal opening of cannula 72 while the distal opening is in fluidcommunication with Schlemm's canal.

FIG. 3A is a stylized perspective view illustrating a portion of eye 20discussed above. Eye 20 includes an iris 30 defining a pupil 32. In FIG.3A, eye 20 is illustrated in a cross-sectional view created by a cuttingplane passing through the center of pupil 32. Eye 20 includes adome-shaped wall 90 having a surface 92 defining an anterior chamber AC.In FIG. 3A, surface 92 is shown having a generally hemispherical shape.Dome-shaped wall 90 of eye 20 comprises a cornea 36 and scleral tissue34. The scleral tissue 34 meets the cornea 36 at a limbus 38 of eye 20.Additional scleral tissue 34 of eye 20 surrounds a posterior chamber PCfilled with a viscous fluid known as vitreous humor. A lens 40 of eye 20is located between anterior chamber AC and posterior chamber PC. Lens 40is held in place by a number of ciliary zonules 42.

Whenever a person views an object, he or she is viewing that objectthrough the cornea, the aqueous humor, and the lens of the eye. In orderto be transparent, the cornea and the lens can include no blood vessels.Accordingly, no blood flows through the cornea and the lens to providenutrition to these tissues and to remove wastes from these tissues.Instead, these functions are performed by the aqueous humor. Acontinuous flow of aqueous humor through the eye provides nutrition toportions of the eye (e.g., the cornea and the lens) that have no bloodvessels. This flow of aqueous humor also removes waste from thesetissues.

Aqueous humor is produced by an organ known as the ciliary body. Theciliary body includes epithelial cells that continuously secrete aqueoushumor. In a healthy eye, a stream of aqueous humor flows out of the eyeas new aqueous humor is secreted by the epithelial cells of the ciliarybody. This excess aqueous humor enters the blood stream and is carriedaway by venous blood leaving the eye.

With reference to FIG. 3A, it will be appreciated that Schlemm's canalSC is disposed inside anterior chamber AC. Schlemm's canal SC is atube-like structure that encircles iris 30. In the illustration of FIG.3A, the cutting plane passing through the center of pupil 32 has alsopassed through Schlemm's canal. Accordingly, two laterally cut ends ofSchlemm's canal SC are visible in the cross-sectional view of FIG. 3A.In a healthy eye, aqueous humor flows out of anterior chamber AC andinto Schlemm's canal SC. Aqueous humor exits Schlemm's canal SC andflows into a number of collector channels. After leaving Schlemm's canalSC, aqueous humor is absorbed into the venous blood stream and carriedout of the eye.

Because of the position of Schlemm's canal SC within the anteriorchamber AC, a Schlemm's canal access cannula inserted through the cornea36 and anterior chamber AC is likely to approach the plane of Schlemm'scanal at an approach angle that is greater than zero. Thus, for example,when using a curved cannula (such as the one shown in FIG. 2) to deliveran implant into Schlemm's canal, the plane of curvature of the cannulawill form a non-zero angle with the plane of Schlemm's canal.

FIG. 3B is a stylized perspective view depicting the surface 92 thatdefines anterior chamber AC of the eye shown in FIG. 3A. In FIG. 3B,surface 92 is shown having a generally hemispherical shape. FIG. 3B maybe used to illustrate some fundamental geometric concepts that will beused below to describe the various ocular implant structures. Geometryis a branch of mathematics concerned with the properties of space andthe shape, size, and relative position of objects within that space. Ingeometry, a sphere is a round object in three-dimensional space. Allpoints on the surface of a sphere are located the same distance r from acenter point so that the sphere is completely symmetrical about thecenter point. In geometry, a point represents an exact location. A pointis a zero-dimensional entity (i.e., it has no length, area, or volume).Geometrically speaking, at any point on a spherical surface, one canfind a normal direction which is at right angles to the surface. For aspherical surface all normal directions intersect the center point ofthe sphere. Each normal direction will also be perpendicular to a linethat is tangent to the spherical surface. In FIG. 3B, a normal line N isillustrated using dashed lines. Normal line N is at right angles tospherical surface 92. Normal line N is also perpendicular to a referenceline TAN. Reference line TAN is tangent to spherical surface 92 in FIG.3B.

As shown in the previous figure, Schlemm's canal is disposed insideanterior chamber AC. An exemplary method in accordance with thisdetailed description may include the step of advancing a distal portionof a cannula into the anterior chamber of the eye. The cannula may thenbe used to access Schlemm's canal, for example, by piercing the wall ofSchlemm's canal with the distal end of the cannula. An ocular implantmay be advanced out of the distal opening of the cannula and intoSchlemm's canal. An exemplary path 94 taken by an ocular implant as itfollows Schlemm's canal along surface 92 is illustrated using a row ofdots in FIG. 3B.

As the ocular implant advances into Schlemm's canal, the ocular implantmay press against the outer major wall of Schlemm's canal and thedome-shaped wall that defines the anterior chamber of the eye. As thebody of the ocular implant presses against the dome-shaped wall of theeye, the dome-shaped wall provides support for Schlemm's canal and theocular implant. The support provided by the dome-shaped wall may berepresented by force vectors. The direction of these force vectors maybe at right angles to points on the spherical surface that defines theanterior chamber. The dome shaped wall comprises scleral tissue that isfirmer than the tissue of Schlemm's canal wall. Accordingly, the outermajor wall of Schlemm's canal may be supported by the dome shaped wallas the ocular implant advances into Schlemm's canal.

During delivery, it is desirable that the ocular implant follow thelumen of Schlemm's canal as it is advanced out the distal opening of thecannula. The ability of the ocular implant to be advanced into andfollow the lumen of Schlemm's canal may be referred to as trackability.Characteristics of an ocular implant that affect trackability includeaxial pushability, lateral flexibility, and overall shape with respectto the shape of Schlemm's canal (e.g., radius of curvature andcross-section profile). Axial pushability generally concerns the abilityof an ocular implant to transmit to the distal end of the ocular implantan axial force applied to the proximal end of the ocular implant.Lateral flexibility concerns the ease with which the ocular implant bodycan bend to conform to the shape of the lumen. Trackability may beadversely effected when twisting forces are applied to a curved body.For example, twisting the body of a curved ocular implant about itslongitudinal axis may cause the curved body to steer away from a desiredpath.

FIG. 4 is a stylized perspective view further illustrating Schlemm'scanal SC and iris 30 shown in FIG. 3A. Schlemm's canal SC and iris 30are disposed inside the anterior chamber AC of the eye. The surface 92that defines the anterior chamber AC of eye 20 is depicted using dashedlines in FIG. 4. In the exemplary embodiment of FIG. 4, Schlemm's canalSC and iris 30 are shown in cross-section, with a cutting plane passingthrough the center of a pupil 32 defined by iris 30. Schlemm's canal SCcomprises a first major side 50, a second major side 52, a first minorside 54, and a second minor side 56. Schlemm's canal SC forms a ringaround iris 30 with pupil 32 disposed in the center of that ring. Withreference to FIG. 4, it will be appreciated that first major side 50 ison the outside of the ring formed by Schlemm's canal SC and second majorside 52 is on the inside of the ring formed by Schlemm's canal SC.Accordingly, first major side 50 may be referred to as an outer majorside of Schlemm's canal SC and second major side 52 may be referred toas an inner major side of Schlemm's canal SC. With reference to FIG. 4,it will be appreciated that first major side 50 is further from pupil 32than second major side 52.

FIG. 22 is an enlarged cross-sectional view further illustratingSchlemm's canal SC. Schlemm's canal SC includes a wall W defining alumen 58. The shape of Schlemm's canal SC is somewhat irregular, and canvary from patient to patient. The shape of Schlemm's canal SC may beconceptualized as a cylindrical-tube that has been partially flattened.The cross-sectional shape of lumen 58 may be compared to the shape of anellipse. A major axis 60 and a minor axis 62 of lumen 58 are illustratedwith dashed lines in FIG. 22.

The length of major axis 60 and minor axis 62 can vary from patient topatient. The length of minor axis 62 is between one and thirtymicrometers in most patients. The length of major axis 60 is between onehundred and fifty micrometers and three hundred and fifty micrometers inmost patients.

With reference to FIG. 22, Schlemm's canal SC has a first major side 50,a second major side 52, a first minor side 54, and a second minor side56. In the exemplary embodiment of FIG. 22, first major side 50 islonger than both first minor side 54 and second minor side 56. Also inthe exemplary embodiment of FIG. 22, second major side 52 is longer thanboth first minor side 54 and second minor side 56.

An exemplary path 94 taken by an ocular implant as it follows Schlemm'scanal along surface 92 is illustrated using a row of dots in FIG. 4. Asthe ocular implant advances into Schlemm's canal, the ocular implant maypress against the outer major wall of Schlemm's canal and thedome-shaped wall that defines the anterior chamber. More particularly,one or more surfaces (e.g., on the struts) of the ocular implant maypress against surface 92, i.e., scleral tissue forming part of thedome-shaped wall of the eye, as the implant moves into and alongSchlemm's canal. The scleral tissue provides support for Schlemm's canaland the ocular implant as it is advanced into and along Schlemm's canal.The support provided by the scleral tissue may be represented by one ormore force vectors with each force vector being at right angles to apoint on the spherical surface that defines the anterior chamber of theeye; these force vectors act on the implant to balance the forcesgenerated by the implant as the implant is inserted into and advancedalong Schlemm's canal.

The interaction between the implant's structure and the tissue formingSchlemm's canal can affect how the implant behaves as it is insertedinto and advanced along Schlemm's canal. For example, the implant mayhave surfaces (hereinafter, “landing surfaces”) that engage scleraltissue within Schlemm's canal as the implant is inserted into andadvanced along Schlemm's canal. If the force vector on a landing surfaceon one side of the implant exceeds the force vector on an opposite sideof the implant, the implant may bend or twist as it is advanced. Inaddition, if the implant has a preset curve, any bending or twisting ofthe implant may direct the curve away from, instead of along, the curveof Schlemm's canal. Also, the implant may have a preferential bendingplane that will affect the orientation of the implant within a curvedinsertion cannula and with the curve of Schlemm's canal as well as theimplant's response to force vectors on its landing surfaces.

For example, an ocular implant in accordance with the present detaileddescription may include a plurality of spines and a plurality of landingsurfaces that seat against the inner surface of the dome shaped wallthat encloses the anterior chamber so that the dome shaped wall providessupporting normal forces to the landing surfaces. The ocular implant maybe configured such that a net twisting moment applied to each spine bythe normal forces supporting the landing surfaces during implantation isreduced or is substantially zero. The ocular implant may also beconfigured such that the normal forces supporting the landing surfacesprimarily or exclusively act to guide each spine along the preferentialbending plane thereof.

FIG. 5A is a photographic image showing a histology slide HS. Histologyslide HS of FIG. 5 was created by sectioning and staining tissue sampledfrom a cadaveric eye. An ocular implant 500 was implanted in Schlemm'scanal SC of the cadaveric eye prior to sectioning. The photograph ofFIG. 5A was created while examining the section of tissue using a lightmicroscope. FIG. 5B is a drawing of the ocular implant 500 used in FIG.5A. Similar to the ocular implants described in, e.g., U.S. Pat. No.7,740,604, US Publ. No. 2009/0082860, U.S. Pat. No. 8,372,026 and USPubl. No. 2011/0009958, implant 500 in FIG. 5B has spines 504alternating with frames 506. The spines and frames have curvedcross-sections, and the circumferential extent of the spinecross-section is less than the circumferential extent of the framecross-section. Implant 500 extends along a curved longitudinal axis, andits curvature plane bisects spines 504. Each frame 506 has two struts508 extending equally from the curvature plane and, therefore, equallyfrom the spines on either side of that frame. Optional openings 510 areformed in each frame. Openings 510 communicate with a channel 532extending along implant 500. Channel 532 has an opening 534 along oneside and extending through the spines and frames. An inlet portion 528of implant 500 is configured to be disposed in the anterior chamber ofthe eye when rest of the implant is disposed in Schlemm's canal.

FIG. 6A is a stylized line drawing illustrating histology slide HS shownin the previous figure. FIG. 6B is a simplified cross-sectional viewillustrating the eye from which the histology sample was taken. FIG. 6Aand FIG. 6B are presented on a single page to illustrate the location ofthe histology sample relative to other portions of the eye 20. Asdiscussed earlier, eye 20 includes a dome-shaped wall 90 having asurface 92 defining an anterior chamber AC. Dome-shaped wall 90 of eye20 comprises a cornea 36 and scleral tissue 34. The scleral tissue 34meets the cornea 36 at a limbus of eye 20. In FIG. 6B, surface 92 isshown having a generally hemispherical shape. In FIG. 6A, ocular implant500 is shown residing in Schlemm's canal SC.

In some embodiments, as shown in FIG. 2, the implant is inserted fromthe anterior chamber through the trabecular meshwork into Schlemm'scanal. Suitable delivery systems for this ab interno implantationprocedure are described in US Publ. No. 2009/0132040, U.S. Pat. No.8,337,509, US Publ. No. 2011/0098809, and U.S. application Ser. No.13/330,592 (filed Dec. 19, 2011). As the implant passes through therelatively soft tissue of the trabecular meshwork, landing surfaces ofthe implant will engage the relatively stiffer scleral tissue boundingSchlemm's canal. The relative position of the landing surfaces withrespect to other structure of the implant (and with respect to thestructure of Schlemm's canal) will govern how reaction forces on thelanding surfaces from this engagement will affect the implant as it isadvanced into Schlemm's canal.

FIG. 7A is a stylized line drawing showing a cross section of an ocularimplant 500 residing in a section of an eye 20 including Schlemm's canalSC. FIG. 7B is a section view showing same cross-sectional portion ofocular implant 500 prior to insertion into Schlemm's canal of eye 20.Implant 500 may be, e.g., one of the implants described in U.S. Pat.Nos. 7,740,604; 8,372,026; US 2009/0082860; or US 2011/0009958. In theview shown in FIG. 7B, no external forces are acting on ocular implant500 so that it is free to assume an undeformed curved shape free ofstress and/or strain. FIG. 7C is a perspective view showing the ocularimplant 500 being inserted into Schlemm's canal through a cannula 72.FIG. 7A, FIG. 7B and FIG. 7C may be collectively referred to as FIG. 7.

Placing FIG. 7A adjacent to FIG. 7B allows comparisons to be drawntherebetween. By comparing FIG. 7A to FIG. 7B, it will be appreciatedthat ocular implant 500 is assuming substantially the same orientationin both figures. It is believed that the tissues of the trabecularmeshwork are quite soft and compliant, and they do not have sufficientstiffness to hold ocular implant 500 in a twisted orientation differentfrom the orientation that the ocular implant takes when no externalforces are acting on it. A twisted implant might therefore not remain inthe desired position within Schlemm's canal.

Ocular implant 500 of FIG. 7B includes a spine 504 and a frame 506. Inthe exemplary embodiment of FIG. 7B, frame 506 comprises a first strut508C and a second strut 508D. As shown, struts 508C and 508D both extendcircumferentially beyond the circumferential extent of spine 504. Firststrut 508C and second strut 508D comprise a first landing surface 542Cand a second landing surface 542D, respectively.

As shown in FIG. 7C, the implant will engage Schlemm's canal tissue asit is inserted into and advanced along Schlemm's canal. The forcevectors from engagement of the implant with scleral tissue partiallybordering Schlemm's canal depend on the relative orientation of landingsurfaces and scleral tissue with respect to the direction of insertion,which in turn depends on the orientation of the implant within thecannula and the relative positions of the landing surfaces on theimplant. As shown in FIG. 7C, during insertion of implant 500 intoSchlemm's canal, landing surface 542C is engaging the scleral tissue STbordering Schlemm's canal more directly than its corresponding landingsurface 542D. This mismatch in engagement may result in a the generationof different reaction forces on landing surfaces 542C and 542D and mayapply bending or twisting moments to the implant that will twist implant500 to move landing surface 542D toward (and perhaps against) scleraltissue ST. The invention described below reduces this bending ortwisting moment.

With reference to FIG. 7, it will be appreciated that first landingsurface 542C of first strut 508C and second landing surface 542D ofsecond strut 508D define a footprint line 538. Footprint line 538contacts ocular implant 500 at a first point 540C and a second point540D. First point 540C is disposed on first landing surface 542C offirst strut 508C. Second point 540D is disposed on second landingsurface 542D of second strut 508D.

A plane 524 is shown intersecting ocular implant 500 in FIG. 7B. In theembodiment of FIG. 7B, the longitudinal axis of ocular implant 500follows a curved path so that the longitudinal axis defines a plane ofcurvature POC that bisects spines 504 and frames 506 and is co-planarwith plane 524 shown in FIG. 7B. A roll angle RA of frame 506 isillustrated using angular dimension lines in FIG. 7B. Roll angle RAextends between plane 524 and footprint line 538. In the embodiment ofFIG. 7B, because corresponding struts 508C and 508D extend equaldistances from the plane of curvature, roll angle RA has a magnitude ofabout ninety degrees. Also in the embodiment of FIG. 7B, footprint line538 is generally orthogonal to the plane of curvature POC of ocularimplant 500.

As an ocular implant advances into Schlemm's canal during a deliveryprocedure, the ocular implant may press against the dome-shaped wallthat defines the anterior chamber. More particularly, one or more strutsof the ocular implant may press against scleral tissue forming part ofthe dome-shaped wall of the eye. Landing surfaces of the ocular implantmay be seated against the outer wall of Schlemm's canal and the scleraltissue as it is advanced into Schlemm's canal. The scleral tissue mayprovide support for the outer wall of Schlemm's canal as the ocularimplant is advanced therein. These supporting reaction forces will actagainst the ocular implant as the implant engages the wall of Schlemm'scanal.

For example, as discussed above with respect to FIGS. 7A and 7C, as theocular implant moves out of delivery cannula 72 into Schlemm's canal,first landing surface 542C of first strut 508C engages scleral tissueST. Because of the slope of the inside back wall of Schlemm's canal, andthe equal heights of the implant struts within the implant's plane ofcurvature, the impact force vector normal to the insertion path of thefirst landing surface 542C against scleral tissue is greater than theimpact force vector normal to the insertion path of the second landingsurface 542D against scleral tissue. The reaction forces from thescleral tissue against implant 500 may therefore cause a twisting orbending of implant 500 as it is advanced into Schlemm's canal that movelanding surface 542 D toward, and perhaps against, scleral tissue ST.

Changing the angle of the insertion cannula with respect to the plane ofSchlemm's canal would change the way the implant's landing surfacesinteract with scleral tissue during insertion and, therefore, anybending or twisting moments applied to the implant. Visualizationrequirements and anterior chamber access limitations may require thecannula to form an angle greater than zero with the plane of Schlemm'scanal. It therefore may be desirable to change the position of theimplant landing surfaces in an effort to reduce the difference in themagnitude of the reaction forces on landing surfaces on opposite sidesof the implant, such as by changing the relative heights of the strutswith respect to the implant's plane of curvature.

FIG. 8A is a stylized line drawing showing an ocular implant 100residing in a section of an eye 20 including Schlemm's canal SC. FIG. 8Bis a section view showing a portion of ocular implant 100 prior toinsertion into Schlemm's canal of eye 20. FIG. 8C is a perspective viewshowing the ocular implant 100 being inserted into Schlemm's canalthrough a cannula 72. In the view shown in FIG. 8B, no external forcesare acting on ocular implant 100 so that it is free to assume anundeformed shape free of stress and/or strain. By comparing FIG. 8A toFIG. 8B, it will be appreciated that ocular implant 100 is assumingsubstantially the same orientation in both figures. As mentioned above,the tissues of the trabecular meshwork are quite soft and compliant, andthey and do not have sufficient stiffness to hold ocular implant 100 ina twisted orientation different from the orientation that the ocularimplant takes when no external forces are acting on it.

Ocular implant 100 of FIG. 8B includes a spine 104 and a frame 106. Inthe exemplary embodiment of FIG. 8B, frame 106 comprises a first strut108C and a second strut 108D. As shown, struts 108C and 108D both extendcircumferentially beyond the circumferential extent of spine 104. Firststrut 108C and second strut 108D comprise a first landing surface 142Cand a second landing surface 142D, respectively. With reference to FIG.8, it will be appreciated that first landing surface 142C of first strut108C and second landing surface 142D of second strut 108D define afootprint line 138. Footprint line 138 contacts ocular implant 100 at afirst point 140C and a second point 140D. First point 140C is disposedon first landing surface 142C of first strut 108C. Second point 140D isdisposed on second landing surface 142D of second strut 108D.

A plane 124 is shown intersecting ocular implant 100 in FIG. 8B. In theembodiment of FIG. 8B, the longitudinal axis of ocular implant 100follows a curved path so that the longitudinal axis defines a plane ofcurvature POC that is co-planar with plane 124 shown in FIG. 8B. Asshown in FIG. 8B, the plane of curvature POC bisects spine 104 so thatthe cross-sectional circumferential extent of spine 104 on one side ofthe plane of curvature is substantially equal to the cross-sectionalcircumferential extent of spine 104 on the other side of the plane ofcurvature.

During implantation, the implant 100 will be oriented with the curvedinsertion cannula 72, as suggested by FIG. 8C, such that the implant'splane of curvature is coplanar with the cannula's plane of curvature.Thus, adjusting the height of the struts with respect to the implant'splane of curvature and curved longitudinal axis will affect the way thatthe implant's landing surfaces engage scleral tissue as the implant isadvanced into and along Schlemm's canal.

A roll angle RB of frame 106 is illustrated using angular dimensionlines in FIG. 8B. Roll angle RB extends between plane 124 and footprintline 138. By comparing FIG. 8B with FIG. 7B described above, it will beappreciated that because strut 108D extends further out of the plane ofcurvature than its opposing strut 108C, the roll angle RB shown in FIG.8B has a magnitude different from the magnitude of roll angle RA shownin FIG. 7B. In the embodiment of FIG. 8B, angle RB has a magnitude otherthan ninety degrees. Also in the embodiment of FIG. 8B, footprint line138 is generally skewed relative to the plane of curvature POC of ocularimplant 100.

Differences in the responses of implant 100 and implant 500 can be seenby comparing FIG. 8 to FIG. 7. As shown in FIGS. 8A and 8C, as theocular implant 100 moves out of delivery cannula 72 into Schlemm'scanal, landing surfaces 142C and 142D engage scleral tissue ST. Becauseof the slope of the inside back wall of Schlemm's canal and the unequalheights of the implant struts with respect to the implant's plane ofcurvature, the impact force vector normal to the insertion path of thefirst landing surface 142C against scleral tissue is closer to (andpossibly equal to) the impact force vector normal to the insertion pathof the second landing surface 142D against scleral tissue. The decreasein the difference between the reaction forces on opposite sides of theimplant will decrease any bending or twisting moments applied to implant100 during insertion and advancement within Schlemm's canal.

FIG. 9 is a perspective view showing ocular implant 500 of FIG. 7. Withreference to FIG. 9, it will be appreciated that ocular implant 500defines a cylindrical surface CYL enclosing a three dimensional volumehaving a shape similar to a cylinder. Ocular implant 500 of FIG. 9includes a spine 504 and a frame 506. In the exemplary embodiment ofFIG. 9, frame 506 comprises a first strut 508C and a second strut 508D.First strut 508C and second strut 508D comprise a first landing surface542C and a second landing surface 542D, respectively. With reference toFIG. 7, it will be appreciated that first landing surface 542C of firststrut 508C and second landing surface 542D of second strut 508D define afootprint line 538. Footprint line 538 contacts ocular implant 500 at afirst point 540C and a second point 540D. First point 540C is disposedon first landing surface 542C of first strut 508C. Second point 540D isdisposed on second landing surface 542D of second strut 508D. Withreference to FIG. 9, it will be appreciated that footprint line 538 lieson the cylindrical surface CYL defined by ocular implant 500.

FIG. 10 is an additional perspective view showing ocular implant 100 ofFIG. 8. With reference to FIG. 10, it will be appreciated that ocularimplant 100 defines a conical surface C enclosing a three dimensionalvolume having a shape similar to a cone. Ocular implant 100 of FIG. 10includes a spine 104 and a frame 106. In the exemplary embodiment ofFIG. 10, frame 106 comprises a first strut 108C and a second strut 108D.First strut 108C and second strut 108D comprise a first landing surface142C and a second landing surface 142D, respectively. With reference toFIG. 7, it will be appreciated that first landing surface 142C of firststrut 108C and second landing surface 142D of second strut 108D define afootprint line 138. Footprint line 138 contacts ocular implant 100 at afirst point 140C and a second point 140D. First point 140C is disposedon first landing surface 142C of first strut 108C. Second point 140D isdisposed on second landing surface 142D of second strut 108D. Withreference to FIG. 10, it will be appreciated that footprint line 138lies on the conical surface C defined by ocular implant 100.

FIG. 11A is a stylized perspective view showing a conical surface C thatis sized and positioned so as to intersect a hemispherical surface S intwo places. A first line L1 is formed where the two surfaces intersect afirst time. A second line L2 is formed where conical surface C andhemispherical surface S intersect a second time. A first point 142A ispositioned on first line L1 and a second point 142B is disposed onsecond line L2.

FIG. 11B is a stylized perspective view showing the ocular implant 100of FIG. 8 disposed inside a chamber V defined by a hemispherical surfaceS. Ocular implant 100 contacts hemispherical surface S at a first point140A, a second point 140B, a third point 140C, a fourth point 140D, afifth point 140E, and a sixth point 140F. First point 140A is disposedon a first landing surface 142A of ocular implant 100. Second point 140Bis disposed on a second landing surface 142B of ocular implant 100.Third point 140C and fourth point 140D are disposed on a third landingsurface 142C and a fourth landing surface 142D, respectively. Fifthpoint 140E and sixth point 140F are disposed on a fifth landing surface142E and a sixth landing surface 142F, respectively.

Applicant has created ocular implants designed to work in harmony withthe dome shaped wall that defines the anterior chamber of the human eye.In some useful embodiments, the ocular implants are configured such thatreaction forces applied to the ocular implant by scleral tissue whilethe ocular implant is being advanced into Schlemm's canal subject theocular implant to pure bending with little or no twisting. The ocularimplant may be configured such that a net twisting moment applied toeach spine by the normal forces supporting the landing surfaces issubstantially zero. The ocular implant may also be configured such thatthe normal forces supporting the landing surfaces primarily orexclusively act to bend each spine along the preferential bending planethereof.

The implant will bend preferentially about the region having thesmallest circumferential extent, i.e., the spine. In the embodimentshown FIGS. 8, 10 and 11B, because the spines extend equally on bothsides of the plane of curvature POC, the plane of curvature and thepreferential bending plane are coplanar. If the roll angle of theimplant is set so that the normal forces on the strut landing surfacesare substantially equal (i.e., the angle of the footprint equals theangle of the back wall of Schlemm's canal), the net forces on theimplant during insertion and advancement will cause the implant to bendalong its preferential bending plane with no net twisting about theplane. In some other useful embodiments (discussed below with respect toFIGS. 15-18 and 19B), the preferential bending plane of each spineextends in a direction that is at right angles to a conical surfacedefined by the ocular implant.

In the embodiment of FIG. 11B, ocular implant 100 defines a conicalsurface C. Ocular implant 100 contacts conical surface C at a firstpoint 140A, a second point 140B, a third point 140C, a fourth point140D, a fifth point 140E, and a sixth point 140F. Due to page sizeconstraints, conical surface C is truncated in FIG. 21. Conical surfaceC intersects hemispherical surface S in two places. First point 140A,third point 140C, and fifth point 140E are disposed on a first lineformed where conical surface C and hemispherical surface S intersect afirst time. Second point 140B, fourth point 140D, and sixth point 140Fare disposed on a second line formed where the two surfaces intersect asecond time.

FIG. 12A, FIG. 12B and FIG. 12C are plan views of the ocular implant 100of FIG. 8 created using multiview projection. FIG. 12A, FIG. 12B andFIG. 12C may be referred to collectively as FIG. 12. It is customary torefer to multiview projections using terms such as front view, top view,and side view. In accordance with this convention, FIG. 12A may bereferred to as a top view of ocular implant 100, FIG. 12B may bereferred to as a side view of ocular implant 100, and FIG. 12C may bereferred to as a bottom view of ocular implant 100. The terms top view,side view, and bottom view are used herein as a convenient method fordifferentiating between the views shown in FIG. 12. It will beappreciated that the implant shown in FIG. 12 may assume variousorientations without deviating from the spirit and scope of thisdetailed description. Accordingly, the terms top view, side view, andbottom view should not be interpreted to limit the scope of theinvention recited in the attached claims.

Ocular implant 100 of FIG. 12 comprises a body 102 that extends along alongitudinal central axis 120. In the exemplary embodiment of FIG. 12,longitudinal central axis 120 follows a curved path such thatlongitudinal central axis 120 defines a curvature plane 122. In someuseful embodiments, the radius of curvature of the ocular implant issubstantially equal to the radius of curvature of Schlemm's canal. Body102 of ocular implant 100 has a distal end 126, a proximal inlet portion128 and an intermediate portion 130 extending between the proximal inletportion 128 and the distal end 126. Intermediate portion 130 comprises aplurality of spines 104 and a plurality of frames 106. The spines 104 ofintermediate portion 130 include a first spine 104A, a second spine 104Band a third spine 104C. The frames 106 of intermediate portion 130include a first frame 106A, a second frame 106B and a third frame 106C.Ocular implant 100 is sized and configured so that the spines and framesare disposed in and supporting Schlemm's canal and the inlet 128 isdisposed in the anterior chamber to provide for flow of aqueous humorfrom the anterior chamber through Schlemm's canal to outflow channelscommunicating with Schlemm's canal.

In FIG. 12, first spine 104A can be seen extending distally beyondproximal inlet portion 128. First frame 106A comprises a first strut108A and a second strut 108B that extend between first spine 104A andsecond spine 104B. With reference to FIG. 12, it will be appreciatedthat second frame 106B abuts a distal end of second spine 104B. In theembodiment of FIG. 12, second frame 106B comprises a first strut 108Cand a second strut 108D that extend between second spine 104B and thirdspine 104C. Third frame 106C can be seen extending between third spine104C and distal end 126 of ocular implant 100 in FIG. 12. Third frame106C comprises a first strut 108E and a second strut 108F.

Body 102 of ocular implant 100 defines a channel 132 that opens into achannel opening 134. With reference to FIG. 12, it will be appreciatedthat channel 132 and channel opening 134 extending together through body102 across first spine 104A, second spine 104B, third spine 104C, firstframe 106A, second frame 106B, and third frame 106C. Optional additionalopenings 110 communicating with channel 132 are disposed between thespines and are surrounded by the struts.

With particular reference to FIG. 12B, it will be appreciated thatcurvature plane 122 intersects first spine 104A, second spine 104B, andthird spine 104C. In the embodiment of FIG. 12A, curvature plane 122bisects each spine into two halves. The two halves of each spine aresymmetrically shaped about curvature plane 122 in the embodiment of FIG.12A. With reference to FIG. 12B and FIG. 12C, it will be appreciatedthat the frames of ocular implant 100 are not symmetric about curvatureplane 122.

FIG. 13A is a plan view showing ocular implant 100 of FIG. 8. FIG. 13Bis an enlarged section view taken along section line B-B shown in FIG.13A. FIG. 13C is an additional enlarged section view taken along sectionline C-C shown in FIG. 13A. FIG. 13A, FIG. 13B and FIG. 13C may becollectively referred to as FIG. 13.

Ocular implant 100 of FIG. 13 comprises a body 102 that extends along alongitudinal central axis 120. Body 102 of ocular implant 100 has adistal end 126, a proximal inlet portion 128 and an intermediate portion130 extending between the proximal inlet portion 128 and the distal end126. Intermediate portion 130 comprises a plurality of spines 104 and aplurality of frames 106. The spines 104 of intermediate portion 130include a first spine 104A, a second spine 104B and a third spine 104C.The frames 106 of intermediate portion 130 include a first frame 106A, asecond frame 106B and a third frame 106C.

In FIG. 13, first spine 104A can be seen extending distally beyondproximal inlet portion 128. First frame 106A comprises a first strut108A and a second strut 108B that extend between first spine 104A andsecond spine 104B. With reference to FIG. 13, it will be appreciatedthat second frame 106B abuts a distal end of second spine 104B. In theembodiment of FIG. 13, second frame 106B comprises a first strut 108Cand a second strut 108D that extend between second spine 104B and thirdspine 104C. Third frame 106C can be seen extending between third spine104C and distal end 126 of ocular implant 100 in FIG. 13. Third frame106C comprises a first strut 108E and a second strut 108F.

Body 102 of ocular implant 100 defines a channel 132 that opens into achannel opening 134. With particular reference to FIG. 13A, it will beappreciated that channel 132 and channel opening 134 extending togetherthrough body 102 across first spine 104A, second spine 104B, third spine104C, first frame 106A, second frame 106B, and third frame 106C. In thisembodiment, the struts on one side of the implant extend further out ofthe plane of curvature that their corresponding struts on the oppositeside of the implant. Thus, as shown in FIG. 13B, strut 108F extendsfurther out of the plane of curvature (corresponding with longitudinalcentral axis 120) than its opposing strut 108E.

FIG. 14A is a perspective view showing ocular implant 100 of FIG. 8.Ocular implant 100 comprises a body 102 extending along a longitudinalcentral axis 120. A first plane 124A is shown intersecting ocularimplant 100 in FIG. 14A. In the embodiment of FIG. 14A, longitudinalcentral axis 120 follows a path that is generally curved such thatlongitudinal central axis 120 defines a plane of curvature that isco-planar with first plane 124A shown in FIG. 14A. A second plane 124B,a third plane 124C, and a fourth plane 124D are also shown intersectingocular implant 100 in FIG. 14A. Second plane 124B, third plane 124C, andfourth plane 124D are all transverse to ocular implant 100 andlongitudinal central axis 120 in the embodiment of FIG. 14A. Moreparticularly, in the exemplary embodiment of FIG. 14A, second plane 124Bis orthogonal to a reference line 136B that lies in first plane 124A andis tangent to longitudinal central axis 120. Third plane 124C isorthogonal to a reference line 136C that lies in first plane 124A and istangent to longitudinal central axis 120. Third plane 124D is orthogonalto a reference line 136D that lies in first plane 124A and is tangent tolongitudinal central axis 120.

Body 102 of ocular implant 100 has a distal end 126, a proximal inletportion 128 and an intermediate portion 130 extending between theproximal inlet portion 128 and the distal end 126. Intermediate portion130 comprises a plurality of spines 104 and a plurality of frames 106.The frames 106 of intermediate portion 130 include a first frame 106A, asecond frame 106B and a third frame 106C. In FIG. 14A, second plane 124Bis shown extending through first frame 106A. Third plane 124C and fourthplane 124D are shown extending through second frame 106B and third frame106C, respectively, in FIG. 14A.

The spines 104 of intermediate portion 130 include a first spine 104A, asecond spine 104B and a third spine 104C. In FIG. 14, first spine 104Acan be seen extending distally beyond proximal inlet portion 128. Firstframe 106A comprises a first strut 108A and a second strut 108B thatextend between first spine 104A and second spine 104B. With reference toFIG. 14, it will be appreciated that second frame 106B abuts a distalend of second spine 104B. In the embodiment of FIG. 14, second frame106B comprises a third strut and a fourth strut that extend betweensecond spine 104B and third spine 104C. Third frame 106C can be seenextending between third spine 104C and distal end 126 of ocular implant100 in FIG. 14. Third frame 106C comprises a fifth strut and a sixthstrut.

With reference to FIG. 14A, it will be appreciated that first plane 124Aintersects the spines of ocular implant 100. In the embodiment of FIG.14A, first plane 124A bisects each spine into two halves. The two halvesof each spine are symmetrically shaped about first plane 124A in theembodiment of FIG. 14A.

In the exemplary embodiment of FIG. 14A, each frame 106 comprises twostruts. In some useful embodiments, each strut includes a landingsurface and each frame is configured to support the spines in a locationoffset from an outer major side of Schlemm's canal while the ocularimplant is in Schlemm's canal and the landing surfaces are engaging theouter major side of Schlemm's canal. In the embodiment of FIG. 14A,first frame 106A, second frame 106B and third frame 106C are eachoriented at a roll angle.

First frame 106A of FIG. 14A comprises a first strut 108A and a secondstrut 108B. The roll angle of first frame 106A may be defined by afootprint line defined by a first landing surface of first strut 108Aand a second landing surface of second strut 108B. In the embodiment ofFIG. 14A, the footprint line will lie in second plane 124B and be skewedrelative to first plane 124A. The angle between the footprint line andfirst plane 124A may be referred to as the roll angle of the frame. Inthe exemplary embodiment of FIG. 14A, second frame 106B and third frame106C have roll angles similar to the roll angle of first frame 106A.

FIG. 14B is a plan view further illustrating first frame 106A and secondplane 124B shown in FIG. 14A. With reference to FIG. 14B, it will beappreciated that first frame 106A has a lateral cross-sectional shape Fthat lies in second plane 124B. First frame 106A comprises a first strut108A and a second strut 108B. First plane 124A is shown intersectingfirst frame 106A in FIG. 14B.

A roll angle RA of first frame 106A is illustrated using angulardimension lines in FIG. 14B. Roll angle RA extends between first plane124A and a first footprint line 138A. In the exemplary embodiment ofFIG. 14, first footprint line 138A is defined by a first point 140A anda second point 140B. First point 140A is disposed on a first landingsurface 142A of first strut 108A. Second point 140B is disposed on asecond landing surface 142B of second strut 108B. As discussed above, inthis embodiment the struts on one side of the implant extend further outof the plane of curvature than their corresponding struts on theopposite side of the implant. Thus, as shown in FIG. 14B, strut 108Bextends further out of the plane of curvature 124A than its opposingstrut 108A.

FIG. 15A, FIG. 15B and FIG. 15C are multi-plan views of yet anotherexemplary ocular implant 300 in accordance with the present detaileddescription. FIG. 15A, FIG. 15B and FIG. 15C may be referred tocollectively as FIG. 15. It is customary to refer to multi-viewprojections using terms such as front view, top view, and side view. Inaccordance with this convention, FIG. 15A may be referred to as a topview of ocular implant 300, FIG. 15B may be referred to as a side viewof ocular implant 300, and FIG. 15C may be referred to as a bottom viewof ocular implant 300. The terms top view, side view, and bottom vieware used herein as a convenient method for differentiating between theviews shown in FIG. 15. It will be appreciated that the implant shown inFIG. 15 may assume various orientations without deviating from thespirit and scope of this detailed description. Accordingly, the termstop view, side view, and bottom view should not be interpreted to limitthe scope of the invention recited in the attached claims.

Ocular implant 300 of FIG. 15 comprises a body 302 that extends along alongitudinal central axis 320. In the exemplary embodiment of FIG. 15,longitudinal central axis 320 follows a curved path such thatlongitudinal central axis 320 defines a curvature plane 322. Body 302 ofocular implant 300 has a distal end 326, a proximal inlet portion 328and an intermediate portion 330 extending between the proximal inletportion 328 and the distal end 326. Intermediate portion 330 comprises aplurality of spines 304 and a plurality of frames 306. The spines 304 ofintermediate portion 330 include a proximal-most spine 304A, anintermediate spine 304B and a distal-most spine 304C. The frames 306 ofintermediate portion 330 include a proximal-most frame 306A, anintermediate frame 306B and a distal-most frame 306C. Ocular implant 300is sized and configured so that the spines and frames are disposed inand supporting Schlemm's canal and the inlet 328 is disposed in theanterior chamber to provide for flow of aqueous humor from the anteriorchamber through Schlemm's canal to outflow channels communicating withSchlemm's canal.

In FIG. 15, proximal-most spine 304A can be seen extending distallybeyond proximal inlet portion 328. Proximal-most frame 306A comprises afirst strut 308A and a second strut 308B that extend betweenproximal-most spine 304A and intermediate spine 304B. With reference toFIG. 15, it will be appreciated that intermediate frame 306B abuts adistal end of intermediate spine 304B. In the embodiment of FIG. 15,intermediate frame 306B comprises a third strut 308C and a fourth strut308D that extend between intermediate spine 304B and distal-most spine304C. Distal-most frame 306C can be seen extending between distal-mostspine 304C and distal end 326 of ocular implant 300 in FIG. 15.Distal-most frame 306C comprises a fifth strut 308E and a sixth strut308F.

Body 302 of ocular implant 300 defines a channel 332 that opens into achannel opening 334. With reference to FIG. 15, it will be appreciatedthat channel 332 and channel opening 334 extending together through body302 across proximal-most spine 304A, intermediate spine 304B,distal-most spine 304C, proximal-most frame 306A, intermediate frame306B, and distal-most frame 306C. Optional additional openings 310communicating with channel 332 are disposed between the spines and aresurrounded by the struts.

FIG. 16A is a plan view showing ocular implant 300 of FIG. 15. FIG. 16Bis an enlarged section view taken along section line B-B shown in FIG.16A. FIG. 16C is an additional enlarged section view taken along sectionline C-C shown in FIG. 16A. FIG. 16A, FIG. 16B and FIG. 16C may becollectively referred to as FIG. 16.

Ocular implant 300 of FIG. 16 comprises a body 302 that extends along alongitudinal central axis 320 which, in this view, lies in the plane ofcurvature of implant 300. Body 302 of ocular implant 300 has a distalend 326, a proximal inlet portion 328 and an intermediate portion 330extending between the proximal inlet portion 328 and the distal end 326.Intermediate portion 330 comprises a plurality of spines 304 and aplurality of frames 306. The spines 304 of intermediate portion 330include a proximal-most spine 304A, an intermediate spine 304B and adistal-most spine 304C. The frames 306 of intermediate portion 330include a proximal-most frame 306A, an intermediate frame 306B and adistal-most frame 306C. As shown, unlike the embodiment of FIG. 8, inthis embodiment the plane of curvature does not bisect the spines.

In FIG. 16, proximal-most spine 304A can be seen extending distallybeyond proximal inlet portion 328. Proximal-most frame 306A comprises afirst strut 308A and a second strut 308B that extend betweenproximal-most spine 304A and intermediate spine 304B. With reference toFIG. 16, it will be appreciated that intermediate frame 306B abuts adistal end of intermediate spine 304B. In the embodiment of FIG. 16,intermediate frame 306B comprises a third strut 308C and a fourth strut308D that extend between intermediate spine 304B and distal-most spine304C. Distal-most frame 306C can be seen extending between distal-mostspine 304C and distal end 326 of ocular implant 300 in FIG. 16.Distal-most frame 306C comprises a fifth strut 308E and a sixth strut308F.

Body 302 of ocular implant 300 defines a channel 332 that opens into achannel opening 334. With reference to FIG. 16, it will be appreciatedthat channel 332 and channel opening 334 extending together through body302 across proximal-most spine 304A, intermediate spine 304B,distal-most spine 304C, proximal-most frame 306A, intermediate frame306B, and distal-most frame 306C. In this embodiment, the struts on oneside of the implant extend further out of the plane of curvature (shownas a dotted line in FIG. 16B) than their corresponding struts on theopposite side of the implant. Thus, as shown in FIG. 16B, strut 308Fextends further out of the plane of curvature than its opposing strut308E. It can also be seen from FIG. 16B that spine 304C extends furtherout of the plane of curvature on one side than on the other and that thestruts 308E and 308F both extend circumferentially equally beyond thecircumferential extend of spine 304C. Thus, implant 300 does not bendpreferentially in the implant's plane of curvature.

FIG. 17A is a perspective view showing ocular implant 300 of FIGS. 15and 16. A first plane 324A is shown intersecting ocular implant 300 inFIG. 17A. Ocular implant 300 of FIG. 17A comprises a body 302 extendingalong a longitudinal central axis 320. In the embodiment of FIG. 17A,longitudinal central axis 320 follows a path that is generally curvedsuch that longitudinal central axis 320 defines a plane of curvaturePOC.

In the embodiment of FIG. 17A, plane of curvature POC is co-planar withfirst plane 324A shown in FIG. 17A. With reference to FIG. 17A, it willbe appreciated that plane of curvature POC would no longer be coplanarwith first plane 324A if ocular implant 300 was rotated. In some methodsin accordance with this detailed description, ocular implant may beadvanced into Schlemm's canal while the plane of curvature of the ocularimplant is co-planar with a plane of curvature of Schlemm's canal.

A second plane 324B and a third plane 324C are shown extendingtransversely across body 302 of ocular implant 300 in FIG. 17A. Withreference to FIG. 17A, it will be appreciated that third plane 324Cextends through a distal-most spine 304C of ocular implant 300. Secondplane 324B is shown extending through a distal-most frame 306C of ocularimplant 300 in FIG. 17A. In the exemplary embodiment of FIG. 17A, secondplane 324B is orthogonal to a reference line 336B. Reference line 336Bis tangent to longitudinal central axis 320 and is shown lying on firstplane 324A in FIG. 17A.

Body 302 of ocular implant 300 has a distal end 326, a proximal inletportion 328 and an intermediate portion 330 extending between theproximal inlet portion 328 and the distal end 326. Intermediate portion330 comprises a plurality of spines 304 and a plurality of frames 306.The frames 306 of intermediate portion 330 include a proximal-most frame306A, an intermediate frame 306B and a distal-most frame 306C. Secondplane 324B is shown extending through distal-most frame 306C in FIG.17A. In the exemplary embodiment of FIG. 17A, body 302 includes a singleintermediate frame 306B. It will be appreciated, however, that body 302include any number of intermediate frames without deviating from thespirit and scope of the present detailed description.

The spines 304 of intermediate portion 330 include a proximal-most spine304A, an intermediate spine 304B and a distal-most spine 304C. In FIG.17A, third plane 324C is shown extending through distal-most spine 304C.In the exemplary embodiment of FIG. 17A, body 302 includes a singleintermediate spine 304B. It will be appreciated, however, that body 302include any number of intermediate spines without deviating from thespirit and scope of the present detailed description.

In FIG. 17A, proximal-most spine 304A can be seen extending distallybeyond proximal inlet portion 328. Proximal-most frame 306A comprises afirst strut 308A and a second strut 308B that extend betweenproximal-most spine 304A and intermediate spine 304B. With reference toFIG. 17, it will be appreciated that intermediate frame 306B abuts adistal end of intermediate spine 304B. In the embodiment of FIG. 17,intermediate frame 306B comprises a first strut and a second strut thatextend between intermediate spine 304B and distal-most spine 304C.Distal-most frame 306C can be seen extending between distal-most spine304C and distal end 326 of ocular implant 300 in FIG. 17. Distal-mostframe 306C comprises a first strut 308E and a second strut 308F. Secondplane 324B is shown extending through distal-most frame 306C in FIG.17A.

FIG. 17B is an enlarged plan view of second plane 324B shown in FIG.17A. With reference to FIG. 17A, it will be appreciated that secondplane 324B intersects a first strut 308E and a second strut 308F ofdistal-most frame 306C. In FIG. 17B, a profile PE of first strut 308E isshown lying on second plane 324B. A profile PF of second strut 308F isalso shown lying on second plane 324B in FIG. 17B. The profile of eachstrut is filled with a cross-hatch pattern in FIG. 17B.

In the embodiment of FIG. 17, the body of ocular implant 300 extendsalong a longitudinal central axis that is generally curved such that thelongitudinal central axis defines a plane of curvature POC that isrepresented by a dashed line in FIG. 17B. A roll angle RA of distal-mostframe 306C is illustrated using angular dimension lines in FIG. 17B.Roll angle RA extends between plane of curvature POC and a firstfootprint line 338C. In the exemplary embodiment of FIG. 17, firstfootprint line 338C is defined by a first point 340E and a second point340F. First point 340E is disposed on a first landing surface 342E offirst strut 308E. Second point 340F is disposed on a second landingsurface 342F of second strut 308F.

Upon advancement of ocular implant 300 into Schlemm's canal, anddepending on the angle of the delivery cannula with respect to the planeof Schlemm's canal during insertion, first landing surface 342E of firststrut 308E and second landing surface 342F of second strut 308F may seatagainst the inner surface of the dome shaped wall that encloses theanterior chamber with the dome shaped wall providing normal forcessupporting the landing surfaces. In some useful embodiments, roll angleRA is selected such that, when ocular implant 300 is advanced intoSchlemm's canal landing surfaces of first strut 308E and second strut308F are seated against the dome-shaped wall that defines the anteriorchamber of the eye with substantially equal force. The decrease in thedifference between the reaction forces on opposite sides of the implantwill decrease any bending or twisting moments applied to implant 300during insertion and advancement within Schlemm's canal.

FIG. 17C is an enlarged plan view of third plane 324C shown in FIG. 17A.As shown in FIG. 17A, third plane 324C intersects distal-most spine304C. Accordingly, distal-most spine 304C is shown in cross-section inFIG. 17C. Distal-most spine 304C has a profile LC that is shown lying onthird plane 324C in FIG. 17C.

In the embodiment of FIG. 17, the body of ocular implant 300 extendsalong a longitudinal central axis that is generally curved such that thelongitudinal central axis defines a plane of curvature POC that isrepresented by a dashed line in FIG. 17C. Because the plane of curvaturePOC does not bisect spine 304C, spine 304C will not bend preferentiallyabout POC.

Upon advancement of ocular implant 300 into Schlemm's canal, the landingsurfaces may seat against the inner surface of the dome shaped wall thatencloses the anterior chamber with the dome shaped wall providing normalforces supporting the landing surfaces. Each spine of ocular implant 300may be configured to preferentially bend along a preferential bendingplane. In some useful embodiments, each spine is rotationally offsetrelative to a first adjacent frame and a second adjacent frame by anangle selected such that the normal forces supporting the landingsurfaces primarily or exclusively act to bend each spine along thepreferential bending plane thereof. In some useful embodiments, eachspine is rotationally offset relative to a first adjacent frame and asecond adjacent frame by an angle selected such that a net twistingmoment applied to each spine by the normal forces is substantially zero.The arrangement described above may minimize any twisting of the ocularimplant body as the ocular implant is advanced into Schlemm's canal aspart of a delivery procedure. This arrangement may also provide bettertrackability than devices that do not include these design features.

As shown in FIG. 17C, distal-most spine 304C of ocular implant 300 has afirst lateral extent EF and a second lateral extent ES. In some usefulembodiments, an aspect ratio of first lateral extent EF to secondlateral extent ES is greater than about one. In some useful embodiments,the aspect ratio of first lateral extent EF to second lateral extent ESis greater than about three. The relationships described above mayadvantageously cause distal-most spine 304C to preferential bend morealong one direction over another by, e.g., bending about the thinnestportion of the device.

With reference to FIG. 17C, it will be appreciated that distal-mostspine 304C has a thickness T. In some useful embodiments, an aspectratio of first lateral extent EF to thickness T may be selected suchthat distal-most spine 304C preferentially bends more along onedirection over another. In some useful embodiments, an aspect ratio offirst lateral extent EF to thickness T is greater than about one. Insome useful embodiments, the aspect ratio of first lateral extent EF tothickness T is greater than about three.

FIG. 18A is an additional perspective view of ocular implant 300 shownin the previous figure. Ocular implant 300 of FIG. 18A includes adistal-most spine 304C and a distal-most frame 306C. In the exemplaryembodiment of FIG. 18A, distal-most frame 306C comprises a first strut308E and a second strut 308F. FIG. 18B is a stylized isometric viewshowing the profiles of distal-most spine 304C, first strut 308E andsecond strut 308F. The profile of distal-most spine 304C was createdwhere a third plane 324C intersects ocular implant 300. Similarly, theprofiles of first strut 308E and second strut 308F were created where asecond plane 324B intersects ocular implant 300 in FIG. 18A.

The profiles of first strut 308E and second strut 308F are labeled PEand PF in FIG. 18B. The profile of distal-most spine 304C is labeled LCin FIG. 18B. With reference to those profiles, it will be appreciatedthat first strut 308E and second strut 308F comprise a first landingsurface 342E and a second landing surface 342F, respectively. In FIG.18B, a first normal force FE is represented by an arrow that is showncontacting first landing surface 342A. A second normal force FF isrepresented by an arrow that is shown contacting second landing surface342A in FIG. 18.

Distal-most spine 304C of FIG. 18, is configured to preferentially bendin a preferential bending direction D shown in FIG. 18B. In some usefulembodiments, ocular implant 300 is configured so that direction Dextends at right angles to a point on a spherical surface that definesthe anterior chamber when the landing surfaces of the ocular implant areseated against the dome-shaped wall that defines the anterior chamber.Also in some useful embodiments, ocular implant 300 is configured sothat direction D extends at right angles to a point on a conical surfacedefined by ocular implant 300. With reference to FIG. 18, it will beappreciated that direction D is generally parallel to the directions offirst normal force vector FE and second normal force vector FF.

In the embodiment of FIG. 18, first strut 308E, second strut 308F anddistal-most spine 304C are configured such that, when ocular implant 300is advanced along Schlemm's canal as part of a delivery procedure thelanding surfaces of first strut 308E and second strut 308F will beseated against the dome-shaped wall defining the anterior chamber. Whenfirst landing surface 342A and second landing surface 342B contact theouter major wall of Schlemm's canal, the dome-shaped wall providesnormal forces to support first strut 308E and second strut 308F. In theembodiment of FIG. 18, ocular implant 300 is configured such that normalforces applied to the landing surfaces of first strut 308E and secondstrut 308F primarily or exclusively act to bend first spine 304C alongits preferential bending plane PBP. In some useful embodiments, eachspine is rotationally offset relative to a first adjacent frame and asecond adjacent frame by an angle selected such that the normal forcessupporting the landing surfaces of the frames primarily or exclusivelyact to bend each spine along the preferential bending plane thereof. Insome useful embodiments, each spine is rotationally offset relative to afirst adjacent frame and a second adjacent frame by an angle selectedsuch that a net twisting moment applied to each spine by the normalforces is substantially zero.

FIG. 19A and FIG. 19B are perspective views showing distal portionsocular implant 100 of FIG. 8 and ocular implant 300 of FIG. 15,respectively. FIG. 19A and FIG. 19B are presented on a single page sothat second ocular implant 300 can be easily compared and contrasted tofirst ocular implant 100. FIG. 19A and FIG. 19B may be collectivelyreferred to as FIG. 19. In FIG. 19, the body of each ocular implantextends along a longitudinal central axis that is generally curved suchthat the longitudinal central axis defines a plane of curvature POC.Each plane of curvature POC is represented by a dashed line in FIG. 19.

Ocular implant 100 includes a distal-most spine 104C, and ocular implant300 includes a distal-most spine 304C. As shown in FIG. 19A, plane ofcurvature POC bisects spine 104C. Spine 104C will bend preferentiallyabout POC. In the embodiment of FIG. 19B, the plane of curvature POCdoes not bisect distal-most spine 304C of ocular implant 300. Spine 304Cwill not bend preferentially in plane POC.

In FIG. 19, two normal forces are shown acting on each ocular implant. Afirst normal force FE is represented by an arrow that is showncontacting a first landing surface of each ocular implant. A secondnormal force FF is represented by an arrow that is shown contactingsecond landing surface of each ocular implant. The arrows representingfirst normal force FE and second normal force FF are force vectorsrepresenting reaction forces provided by the dome-shaped wall of theeye. The dome-shaped wall of the eye provides support for the outermajor wall of Schlemm's canal and the ocular implant during delivery.The support provided by the dome-shaped wall may be represented by theforce vectors shown in FIG. 19. With reference to FIG. 19, it will beappreciated that direction D is generally parallel to the directions offirst normal force vector FE and second normal force vector FF.

FIG. 20 is a perspective view showing an exemplary ocular implant 300 inaccordance with this detailed description. Ocular implant 300 of FIG. 20comprises a body 302 including a plurality of spines 304 and a pluralityof frames 306. The frames 306 of body 302 include a first frame 306A, asecond frame 306B and a third frame 306C.

First frame 306A comprises a first strut 308A and a second strut 308B.First strut 308A and second strut 308B comprise a first landing surface342A and a second landing surface 342B, respectively. First landingsurface 342A of first strut 308A and second landing surface 342B ofsecond strut 308B define a first footprint line 338A. Second frame 306Bcomprises a first strut 308C and a second strut 308D. First strut 308Ccomprises a first landing surface 342C and second strut 308D comprises asecond landing surface 342D. First landing surface 342C of first strut308C and second landing surface 342D of fourth strut 308D define asecond footprint line 338B. Third frame 306C includes a first strut 308Eand a second strut 308F. First strut 308E and second strut 308F have afirst landing surface 342E and a second landing surface 342F,respectively. First landing surface 342E of first strut 308E and secondlanding surface 342F of second strut 308F define a third footprint line338C. In FIG. 20, first footprint line 338A, second footprint line 338B,and third footprint line 338C are shown intersecting at an apex 344 of aconical surface C.

Body 302 of ocular implant 300 has a distal end 326, a proximal inletportion 328 and an intermediate portion 330 extending between proximalinlet portion 328 and distal end 326. Intermediate portion 330 of body302 includes first frame 306A, second frame 306B, third frame 306C and aplurality of spines 304. The spines 304 of intermediate portion 330include a first spine 304A, a second spine 304B and a third spine 304C.In FIG. 20, first frame 306A can be seen extending between first spine304A and second spine 304B. With reference to FIG. 20, it will beappreciated that second frame 306B extends between second spine 304B andthird spine 304C. In the embodiment of FIG. 20, third frame 306C extendsbetween third spine 304C and distal end 326 of ocular implant 300 inFIG. 20.

In the embodiment of FIG. 20, each of first spine 304A, second spine304B, and third spine 304C are configured to preferentially bend in adirection that is at right angles to conical surface C defined by firstfootprint line 338A, second footprint line 338B, and third footprintline 338C.

FIG. 21 is a stylized perspective view showing Schlemm's canal SCencircling an iris 30. With reference to FIG. 21, it will be appreciatedthat Schlemm's canal SC may overhang iris 30 slightly. Iris 30 defines apupil 32. Schlemm's canal SC forms a ring around iris 30 with pupil 32disposed in the center of that ring. With reference to FIG. 21, it willbe appreciated that Schlemm's canal SC has a first major side 50, asecond major side 52, a first minor side 54, and a second minor side 56.With reference to FIG. 21, it will be appreciated that first major side50 is further from pupil 32 than second major side 52. In the exemplaryembodiment of FIG. 21, first major side 50 is an outer major side ofSchlemm's canal SC and second major side 52 is an inner major side ofSchlemm's canal SC.

For purposes of illustration, a window 70 is cut through first majorside 50 of Schlemm's canal SC in FIG. 21. Through window 70, an ocularimplant can be seen residing in a lumen defined by Schlemm's canal. Theocular implant shown in FIG. 21 is ocular implant 300 shown in theprevious figure. Ocular implant 300 comprises a body 302 including aplurality of spines and a plurality of frames 306. The frames 306 ofbody 302 include a first frame 306A, a second frame 306B and a thirdframe 306C. First frame 306A comprises a first landing surface 342A anda second landing surface 342B. First landing surface 342A and secondlanding surface 342B define a first footprint line 338A. Second frame306B comprises a first landing surface 342C and a second landing surface342D. First landing surface 342C and second landing surface 342D definea second footprint line 338B. Third frame 306C comprises a first landingsurface 342E and a second landing surface 342F. First landing surface342E and second landing surface 342F define a third footprint line 338C.In the embodiment of FIG. 21, first footprint line 338A, secondfootprint line 338B, and third footprint line 338C intersect at an apexof a conical surface C. Due to page size constraints, conical surface Cis truncated in FIG. 21.

In the embodiment of FIG. 21, the landing surfaces of each frame areconfigured to seat against the outer major side 50 of Schlemm's canalSC. In the eye, the outer major side of Schlemm's canal is backed byscleral tissue. Accordingly, in the exemplary embodiment of FIG. 21, thelanding surfaces of each frame will be seated against and supported byscleral tissue of the eye. Normal supporting forces will be applied tothe landing surfaces of the struts by the scleral tissue. Applicant hascreated ocular implants designed to work in harmony with the dome shapedwall that defines the anterior chamber of the human eye. In some usefulembodiments, the ocular implants are configured such that reactionforces applied to the ocular implant by scleral tissue while the ocularimplant is being advanced into Schlemm's canal subject the ocularimplant to pure bending with little or no twisting. The ocular implantmay be configured such that a net twisting moment applied to each spineby the normal forces supporting the landing surfaces is substantiallyzero. The ocular implant may also be configured such that the normalforces supporting the landing surfaces primarily or exclusively act tobend each spine along the preferential bending plane thereof. In someuseful embodiments, the preferential bending plane of each spine extendsin a direction that is at right angles to a conical surface defined bythe ocular implant.

While exemplary embodiments of the present invention have been shown anddescribed, modifications may be made, and it is therefore intended inthe appended claims to cover all such changes and modifications whichfall within the true spirit and scope of the invention.

What is claimed is:
 1. An ocular implant adapted to be disposed withinSchlemm's canal of a human eye and configured to support Schlemm's canalin an open state, the ocular implant comprising: a body extending alonga curved longitudinal central axis and configured to bend in a curvatureplane, the body comprising a central channel that opens into a channelopening, the body further comprising first and second frames and a spineinterposed between the first and second frames, wherein the channelopening extends through the body across from the spine, wherein theplane of curvature bisects the spine, the body having dimensions adaptedto be fit within Schlemm's canal; each frame comprising a strut on oneside of the curvature plane of the body and a second strut on anopposite side of the curvature plane of the body, the first strutextending further out of the curvature plane than the correspondingsecond strut on the opposite side of the body such that the first andsecond frames are not symmetric about the curvature plane.
 2. The ocularimplant of claim 1 wherein the body has a curved resting shape along thecurvature plane.
 3. The ocular implant of claim 1 wherein the spinecomprises a first spine, the implant further comprising a third frameand a second spine interposed between the second and third frames,wherein the channel opening extends through the body across from thesecond spine, the third frame comprising a first strut on one side ofthe curvature plane of the body and a second strut on an opposite sideof the curvature plane of the body, the first strut of the third frameextending further out of the curvature plane than the correspondingsecond strut such that the third frame is not symmetric about thecurvature plane.
 4. The ocular implant of claim 3 wherein the first,second and third frames are substantially identical.
 5. The ocularimplant of claim 1 further comprising a second opening bordered by thefirst and second struts of the first frame and a third opening borderedby the first and second struts of the second frame.